1. Field of Invention
This invention relates to integrated circuit (IC) fabrication, and more particularly relates to a method of selectively removing a patterned hard mask.
2. Description of Related Art
Hard mask is usually used in patterning processes in IC fabrication for higher resistance to dry etching. After the target layer is patterned with a patterned hard mask, the hard mask may be retained, entirely removed or selectively removed, as required by later steps. For example, in manufactures of certain products, after a poly-Si layer is defined into gate electrodes of MOS transistors and resistors and spacers are formed on their sidewalls, the mask patterns on the gate electrodes will be retained and those on the resistors will be removed for salicide formation. In such case, conventionally, only the mask patterns on the gate electrodes are covered by photoresist before the removal.
However, during the etching of the mask patterns on the resistors, the spacer on the sidewall of each resistor is also damaged much so that the salicide is formed thicker than required at the top edge of each resistor.